Team,

I have a 2002 AP1 with just over 72,000 miles on it. Today I installed a Skunk2 Alpha header and a Q300 Invidia exhaust. Kept the stock cat and sensors. When I brought it home I noticed a slight rough idle but very minimal.

Is this normal? It hasn’t been tuned since the modifications.

 

No, do the idle relearn process.

 

Perhaps its idling normally, but now you can feel/hear any irregularities. Plus, its re-learning since you likely unplugged the battery to do the install.

Its not like the F20/22 idle is glass smooth anyway. And you've modified the scavenging effect of the exhaust.

If there is no CEL on, I would just ignore it. The car may adjust itself a bit to the new configuration anyway.